Star-shaped cutting insert for a front and back chamfering rotary milling cutter

A double-sided star-shaped cutting insert (32), comprising

• opposing insert top and bottom surfaces (42, 44) and an insert peripheral surface (46) extending therebetween;
• a centrally located insert axis (C) extending through the insert top and bottom surfaces (42, 44), the cutting insert (32) being indexable on each of the insert top and bottom surfaces (42, 44) about the insert axis (C);
• circumferentially alternating outer and inner corner portions (50, 52), the inner corner portions (52) being located closer to the insert axis (C) than the outer corner portions (50);
• a plurality of cutting portions (54), each cutting portion (54) defined by one of said outer corner portions (50), an adjacent first inner corner portion (52a) rotationally forward thereof and an adjacent second inner corner portion (52b) located rotationally rearward thereof;
• a median plane (M) passing through the insert peripheral surface (46) midway between the top and bottom surfaces (42, 44);
• a bisector plane (PS) formed at each cutting portion (54), each bisector plane (PS) containing the insert axis (C), and bisecting both an associated outer corner portion (50) and an associated opposite inner corner portion (52);
• a median axis (AS) formed at an intersection of each bisector plane (PS) and the median plane (M), each median axis (AS) intersecting the insert axis (C), and passing through both an associated outer corner portion (50) and an associated opposite inner corner portion (52);
• wherein:
• each cutting portion (54) comprising a cutting edge (58) formed at the intersection of the insert top and peripheral surfaces (42, 46);
• each cutting edge (58) comprises a front chamfering cutting edge (58a) extending from the outer corner portion (50) to the first inner corner portion (52a) and a back chamfering cutting edge (58a) extending from the outer corner portion (50) to the second inner corner portion (52b);
• the cutting insert (32) has a number N cutting portions and is N-way indexable on both the top and bottom surfaces, N being 3, 5, 7 or 9;
• the cutting insert (32) is mirror symmetrical about the median plane (M);
• the cutting insert (32) is mirror symmetrical about each bisector plane (PS);
• the cutting insert (32) is 180° rotationally symmetrical about each median axis (AS);
• and
• the cutting insert (32) is devoid of cutting edges which extend between top and bottom surfaces (42, 44) in a thickness direction of the cutting insert (32) parallel to the insert axis (C).